Mapping must be called using ServiceAdapter

Im getting the above error. I cant quite figure out what its supposed to mean.? Looking at this test, I assume that its an old errormessage, and its supposed to be ServiceMapper instead of ServiceAdapter?
However, I am already using the ServiceMapper like this:

services.AddSingleton<IMapper, ServiceMapper>();

I setup my mapping configuration like this:

TypeAdapterConfig<Course, InProgressCourseViewDTO>.NewConfig()
    .AfterMappingAsync(async (course, viewDto) =>
    {
        await Helpers.SetImageUrls(course, viewDto);
    });

public static async Task SetImageUrls(Course course, InProgressCourseViewDTO dto)
{
            var blobClient = MapContext.Current.GetService<IBlobClient>();
            var blobEntry = await blobClient.GetPublicBlobAsync(course.blobReference.EntryId);
            dto.Url = blobEntry?.Url ?? default;
}

and using it like this:

private async Task<InProgressCourseViewDTO> MapInProgress(Course course)
{
    var view = await course.BuildAdapter().AdaptToTypeAsync<InProgressCourseViewDTO>();
    return view;
}

Start with the referenced InjectionTest.cs test and trace the ServiceMapper registration against the BuildAdapter().AdaptToTypeAsync call. Reproduce the error using the snippets and inspect how MapContext.Current resolves services during AfterMappingAsync. Done means determining whether the message or setup is incorrect and documenting or covering the expected behavior with a focused test.